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This
is Gliese
581 d
it's a large rocky earth-like planet
the nearest known
it's just possible that this world, or one like it
could in the future become home to the human race
a second sanctuary against the unforgiving blackness of space
discovered in 2007
it's seven times bigger than earth
it orbits a star smaller
and redder then our own
but it lies at just the right distance from its sun to allow water to exist
on the surface
but even if this is the perfect
home away from home
there is a fundamental problem we will have to have overcome
Gliese
is a very
very long way away
more than twenty lightyears
from earth
that's one hundred and twenty trillion miles
to get some idea of this extraordinary distance
and the challenge it presents
I am going to imagine that we could hitch a ride on the
fastest
man-made object
in existence
Voyager 1
was launched in 1977
now over thirty years old
it's traveled more then thirteen billion miles
its mission so far has taken it to Jupiter and Saturn. By using their gravity to boost its speed
the little spacecraft has entered the record books. It might not look fast
but Voyager is racing trough space at eleven miles a second.
On earth, eleven miles a second
looks like this
it's thirty nine thousand miles an hour
at this speed we could circle the globe
one and a half times in an hour
so how long would it take a spaceship traveling at Voyager's speed to get to
the nearest earth-like planet, Gliese?
The answer reveals the true scale of the cosmos
for even traveling at eleven miles
a second
the journey to Gliese would still take over 350.000 years
I think we have a chance to become a lasting part
of the ever changing universe
and to discover wat other wonders it might hold. But to do this we will have to develop new technology on an enormous scale
and that's going to take some serious engineering
if we could build a machine capable of traveling to other solar systems
we'd open up a fascinating possibility
the survival of the human race
for billions of years
present-day engineers have begun thinking about the principles of
building such a ship
this is what it might look like
it could use atomic energy
or perhaps more exotic fuel such as antimatter supplying it with enormous
amounts of power
yet I think the main challenges won't be technical. The first will be financial
the cost of constructing an interstellar spacecraft would be huge
and for the society that made it
there would be little payback
they would never see it again
so constructing such a machine will either be the greatest active generosity
in history
or it will have to be funded
by the travelers themselves. And that
raises the second problem
even if it could travel mind-numbingly fast, say a thousand times faster then
Voyager
eleven thousand miles a second
a journey to the nearest star system would still take
73 years